Sexual minority (SM) women are an understudied population and there is no research on prenatal substance use in younger cisgender SM women. However, SM women (especially bisexual and mostly heterosexual women) are 2-4 times more likely to experience a teenage pregnancy than heterosexual women. SM women initiate cigarette, alcohol and marijuana use at much younger ages, and continue to use more of these substances into young adulthood. Despite these striking disparities in rates of teen pregnancy and pre- pregnancy substance use, there have been no studies of prenatal substance use in young SM women. The goal of this study is to address that gap in the literature by collecting additional data from pregnant SM women ages 13-21 from an existing cohort, the YoungMoms study. SM women from the YoungMoms study will be recruited to complete an online survey (n=85) and qualitative interviews (n=20). The pregnant SM women will be matched for age and race with pregnant heterosexual (non-SM) women from the YoungMoms study, to compare their rates of substance use and other risk factors such as experiences of violence, discrimination, stress, and depression. The aims of this study are twofold: (1) Identify the prevalence and types of tobacco, alcohol, cannabis and other illicit drug use before and during pregnancy in young pregnant SM women and compare them to rates in non-SM women; and (2) Compare the rates of risk factors for prenatal substance use and other syndemic factors in young pregnant SM and non-SM women. Qualitative interviews will be used to elucidate factors related to prenatal substance use that may be specific to young SM women. This is a logical extension and well within the scope of the parent study, which was designed to examine patterns of perinatal cannabis and tobacco use in younger pregnant women. This study is a cost-effective way to accelerate research on SM women and provide much-needed data on prenatal substance use in this high-risk population. The study represents an entirely new shift in focus on teen and young adult mothers with implications for both research and clinical practice. Obstetric providers may not realize how many of their younger patients are SM, nor the specific risk factors related to prenatal substance use in this vulnerable population.